This is insane. I just bought a new pc and decided to replace some new hardware with the old one, like the HD, modem and such because some of it is better. Cutting to the chase... I finally got xp pro installed on my older drive, and with that done I had a dual-boot, one with xp home and another with xp pro. The problem is, once I take one of the hard drives out and put the other one in master, the system boots directly to the cd-rom! I've struggled with the bios settings for 2 days now to no avail. No matter what I do, this is what I get(this is usually the message before one enters the OS): "Verifying DMI pool Data... Boot from Atapi cd-rom: Failure DISK BOOT FAILURE" My drive IS in master, it has xp pro installed on it, technically it should directly boot my OS right? My jumper settings are all good and I've checked them a thousand times. I changed bios settings to ignore the cd-rom and yet it still does the same. I press enter and the same message appears over and over, it's like I only have a cd-rom drive installed. My cd-rom came pre-installed into secondary master. Is this a hardware issue? Howcome it doesn't go to my drive? I even used a recovery cd that came with my computer and formatted/repaired/cleaned my drive, and I'm starting to think it may be completely unrelated to the main problem... Please help me, I'm really desperate to try anything out. Thanks in advance.

My mistake, it was: "Verifying DMI pool Data... Boot from Atapi cd-rom: Failure DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER"

Check your IDE cables,could be a bad cable or connection.

I don't know whether this will help, but Win XP (either flavour) doesn't like it's hard drives moved. For example, taking a WINXP Hard drive from one machine and placing it into another results in a STOP exception error (this is by microsofts design) and you have to reinstall XP over the top to get it going. Will your computer boot if you change the HDD's back to their original positions?

You have a dualboot system with XPHome on one drive and Pro on the other. Presuming one is C drive and other is D, You cannot just remove the C drive and turn D into master and expect it to boot. The bootsequence files are contained on the physical C disk. The operating system on the C drive knows it is on C. The one on D knows it is on D. It is not possible to change the drive label of System files. If you want to change your HDD configuration you will have to format and reinstal the operating system.

Thank you all for the replies, greatly appreciated. "Will your computer boot if you change the HDD's back to their original positions?" Yes the hard drives do work if I put them back on as their original position! The problem always happens when one of them is removed. "You have a dualboot system with XPHome on one drive and Pro on the other. Presuming one is C drive and other is D, You cannot just remove the C drive and turn D into master and expect it to boot. The bootsequence files are contained on the physical C disk. The operating system on the C drive knows it is on C. The one on D knows it is on D." Richard, I think you've found out what the exact problem is, and I actually thought about this for a while. Yes, my drives are C and D, and one has xp home on it and the other xp pro and they're set to have a dual-boot on startup. But I removed C and put D as master. If what you say is right, which I think it might very well be, how should I go about completely formatting my drive(s)? One is already out of the box(the one with the boot sequence files), so is there a way to go around this problem without reinstalling the other drive again? Or do I need to format and reinstall everything on the drive containing the boot sequence files?